JP2005306169A - Soundproof structure of power unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress noise emitted from a transmission case of a power unit by using a simple construction, in the power unit being configured so that its transmission case forming a storage chamber to store a transmission is installed continuously in such a way as covering part of the engine body from the side and also extending toward the driving wheels, and that a soundproof cover to cover the outer side faces of the transmission case is installed on the transmission case. <P>SOLUTION: Soundproofing material members 137-140 to partition the space between the transmission case 71 and the soundproof cover 129 into a plurality of spaces including at least one closed spaces 134-136 are installed between the transmission case 71 and the soundproof cover 129. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  According to the present invention, a transmission case that forms a storage chamber for accommodating a transmission is connected to the engine body so as to cover a part of the engine body from the side and extend to the drive wheel side. The present invention relates to a power unit to which a soundproof cover that covers an outer surface of a transmission case is attached, and more particularly to improvement of a soundproof structure so as to suppress generation of noise from the transmission case.

For example, Patent Document 1 and Patent Document 2 have already been known in which a sound absorbing material is sandwiched between an outer surface of a transmission case and a soundproof cover that covers the outer surface of the transmission case.
Japanese Patent No. 2796105 Japanese Patent No. 3156079

  However, in the above-mentioned conventional one, the sheet-like sound absorbing material is sandwiched between the transmission case and the soundproof cover, so that the noise generation is suppressed only by absorbing the noise emitted from the transmission case with the sound absorbing material. It is hard to say that the noise prevention effect is sufficiently obtained.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a soundproof structure in a power unit that can sufficiently suppress noise emitted from a transmission case with a simple structure.

  In order to achieve the above object, according to the first aspect of the present invention, a transmission case forming a housing chamber for housing a transmission covers a part of the engine body from the side and extends to the drive wheel side. Thus, in the power unit in which the soundproof cover that covers the outer surface of the transmission case is attached to the transmission case, the space between the transmission case and the soundproof cover is divided into a plurality of spaces including at least one closed space. A soundproofing material is disposed between the transmission case and the soundproofing cover.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect of the invention, one surface of the soundproof material formed in a string shape by cutting and forming a urethane sheet is formed of the transmission case and the soundproof cover by an adhesive. It is characterized by being adhered to any of the above.

  Furthermore, the invention described in claim 3 is a V-belt type automatic transmission including a drive pulley device and a driven pulley device in addition to the configuration of the invention described in claim 1 or 2, and is cooled in the accommodation chamber. An outside air intake for taking in air is provided on the side wall of the transmission case at a portion facing the drive pulley device, and the soundproof cover is substantially half of the outer surface of the transmission case on the side corresponding to the driven pulley device. It is formed in the shape which covers a part.

  According to the first aspect of the present invention, noise emitted from the transmission case is suppressed by being absorbed by the soundproofing material disposed between the transmission case and the soundproof cover, and is formed between the transmission case and the soundproof cover. It is suppressed by preventing the sound resonance from occurring in at least one closed space, and the space between the transmission case and the soundproof cover is divided into a plurality of spaces by a soundproof material. A sufficient noise prevention effect can be obtained.

  According to the invention of claim 2, the soundproofing material is formed in a string shape by cutting and molding a urethane sheet, and a conventional soundproofing material having a shape corresponding to the shape of the soundproofing cover is used. Compared to those, it is possible to increase the yield when forming soundproofing materials, and it is possible to attach the soundproofing cover to the transmission case with the soundproofing material bonded to either the transmission case or the soundproofing cover. Increases productivity at the time.

  Furthermore, according to the invention described in claim 3, it is possible to increase the productivity by arranging the soundproofing material between the transmission case and the soundproof cover without considering the outside air intake port provided in the transmission case.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 9 show an embodiment of the present invention, FIG. 1 is a side view of a power unit and a rear wheel, FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, and FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, FIG. 5 is a sectional view taken along line 5-5 in FIG. 3, FIG. 6 is an enlarged transverse sectional view of the driven pulley device, and FIG. FIG. 8 is a view of the case cover and the soundproof cover as viewed from the direction of arrows 8-8 in FIG. 2, and FIG. 9 is a test result of the noise generation state. FIG.

  First, in FIGS. 1 and 2, a power unit including an engine E disposed in front of a rear wheel WR as drive wheels and a V-belt type automatic transmission M provided between the engine E and the rear wheel WR. P is mounted on a body frame (not shown) of the scooter type motorcycle, and a rear wheel WR disposed on the right side of the rear portion of the power unit P is pivotally supported on the rear portion of the power unit P.

  The engine body 11 of the engine E includes a crankcase 12 that rotatably supports a crankshaft 16 having a rotation axis parallel to the rotation axis of the rear wheel WR, a cylinder block 13 that is coupled to the crankcase 12, and a crankcase 12 And a head cover 15 coupled to the cylinder head 14 on the opposite side of the cylinder block 13.

  The cylinder block 13 is disposed so that the axis of the cylinder bore 17 provided in the cylinder block 13, that is, the cylinder axis C1 is substantially horizontal as it rises slightly forward along the front-rear direction of the motorcycle. The crankcase 12 includes a pair of case halves 12a and 12b that include the cylinder axis C1 and are coupled by a plane perpendicular to the axis of the crankshaft 16, and one of the case halves 12a and 12b. A ball bearing 18 is interposed between the half body 12 a and the crankshaft 16. Between the other case half body 12 b and the crankshaft 16, there is a roller bearing 19 and an annular shape disposed outward from the roller bearing 19. A seal member 20 is interposed.

  A combustion chamber 23 is formed between the cylinder head 14 and a piston 21 slidably fitted in the cylinder bore 17. From the intake valve 24 that controls intake air to the combustion chamber 23 and the combustion chamber 23. The exhaust valve 25 that controls the exhaust of the cylinder is arranged in the cylinder head 14 so as to be arranged in a substantially V shape on a projection view on a plane orthogonal to the rotational axis of the crankshaft 16. A spark plug 26 facing the combustion chamber 23 is attached to the left side surface of the cylinder head 14 with the motorcycle facing forward in the traveling direction.

  Between the cylinder head 14 and the head cover 15, a camshaft 27 having an axis parallel to the axis of the crankshaft 16 and rotatably supported by the cylinder head 14 and having intake and exhaust cams 28 and 29 is included. A valve operating mechanism 30 is accommodated so as to open and close the intake valve 24 and the exhaust valve 25.

  A driven sprocket 31 is fixed to one end of the camshaft 27. On the other hand, a first driving sprocket 32 is fixed to a position corresponding to the driven sprocket 31 on the outer side of the ball bearing 18 in the crankshaft 16, and the first driving sprocket 32 and the driven sprocket 31 are endless. The cam chain 33 is wound, and the cam chain 33 is housed in a chain chamber 34 formed over the cylinder block 13, the cylinder head 14 and the head cover 15 so as to be able to run. The cam shaft 27 is rotationally driven by the first drive sprocket 32, the driven sprocket 31, and the cam chain 33 at a rotational speed that is ½ of the rotational speed of the crankshaft 16.

  Referring also to FIG. 3, the crankshaft 16 includes a pair of crank webs 16 a and 16 b that are opposed to each other at an interval in the axial direction, and both ends of the crank pin 37 are connected to the crank webs 16 a and 16 b. Is done. On the other hand, one end of a connecting rod 38 is connected to the piston 21, and the other end of the connecting rod 38, that is, the large end 38 is connected to the crank pin 37 via a needle bearing 39.

  A second drive sprocket 40 is fixed to the crankshaft 16 on the outer side of the first drive sprocket 31. On the other hand, an oil pump 41 (see FIG. 1) for pumping oil from the lower part in the crankcase 12 and a cooling water pump 42 (FIG. 1) for circulating cooling water through a cooling jacket 43 provided in the cylinder block 13 and the cylinder head 14. Are connected to the same axis on the lower side of the crankcase 12, and rotational power is transmitted from the second drive sprocket 40 to the oil pump 41 and the cooling water pump 42 via the chain 44.

  Outside the second drive sprocket 40, a stator 47 fixed to a right cover 45 attached to the right side surface of the crankcase 12 and an outer rotor fixed to the crankshaft 16 so as to surround the stator 47. The generator 46 provided with 48 is arrange | positioned.

  Between the second drive sprocket 40 and the outer rotor 48, there is disposed a driven gear 49 that coaxially surrounds the crankshaft 16 and is rotatably supported by the crankshaft 16. The outer rotor 48 is connected via a one-way clutch 50. Thus, rotational power from a starter motor (not shown) can be input to the driven gear 49, and the driving force from the starter motor is transmitted to the crankshaft 16 when the engine E is started. The power from the crankshaft 16 is not transmitted to the starter motor side by the action of the clutch 50.

  A cylindrical support cylinder 45a surrounding the right end of the crankcase 12 is integrally projected at the center of the inner surface of the right cover 45, and an annular seal is provided between the support cylinder 45a and the crankshaft 16. A member 53 is interposed, and an oil chamber 54 into which the right end portion of the crankshaft 16 is inserted is formed in the central portion on the inner surface side of the right cover 45, and oil from the oil pump 41 is guided to the oil chamber 54. An oil passage 55 provided in the crankcase 12 and the right cover 45 communicates.

  The crankshaft 16 is provided with a bottomed first oil passage hole 56 that allows the outer end to pass through the oil chamber 54 so as to close the inner end at a position substantially corresponding to the ball bearing 18. The crankpin 37 is provided with a bottomed second oil passage hole 57 coaxially open to the ball bearing 18 for weight reduction and oil supply. On the other hand, an annular mounting recess 58 that faces the open end of the second oil passage hole 57 is formed on the outer surface of the crankshaft 16 on the ball bearing 18 side of one crank web 16a. An outer peripheral portion of an oil delivery plate 59 formed in an annular and dish shape so as to cover the open end of 57 is caulked and fixed to the mounting recess 58.

  The crankshaft 16 is provided with a first communication hole 60 that guides oil from the first oil passage hole 56 between the oil delivery plate 59 and the crank web 16a. Further, the crank pin 37 is provided with a second communication hole 61 that guides the oil in the second oil passage hole 57 to the needle bearing 39 side.

  Therefore, the oil introduced from the oil pump 41 through the oil passage 55 into the oil chamber 54 is between the first oil passage hole 56, the first communication hole 60, the oil delivery plate 59 and the crank web 16a, the second oil passage hole 57, Oil is supplied to the needle bearing 39 through the second communication hole 61. The crankshaft 16 is also provided with a third communication hole 62 that guides oil from the first oil passage hole 56 between the crankshaft 16 and the driven gear 49.

  By the way, the oil supplied to the needle bearing 39 is used for lubrication between the large end portion 38a of the connecting rod 38 and the crank pin 37, and is scattered with the rotation of the crankshaft 16, and the oil is scattered. An oil hole 63 for guiding a part of the oil to the roller bearing 19 side is provided in the other crank web 16 b having an axis parallel to the axis of the crankshaft 16.

  Referring also to FIG. 4, the other crank web 16b is provided with a weight portion 16ba on the opposite side of the connecting portion of the crank pin 37 with respect to the axis C2 of the crankshaft 16, and the crank web 16b The inner side surface extends in parallel with the arcuate high-order surface 64 corresponding to the weight portion 16ba, the straight line L passing through the axis line C2 of the crankpin 16 and the axis C2 of the crankshaft 16, and the connecting portion and weight of the crankpin 37. It consists of a middle surface 65 extending in a strip shape between the portions 16ba and another lower surface 66, and the middle surface 65 is formed so as to form a stepped portion 67 between the lower surface 66 and the lower surface 66. The high level surface 64 is formed so as to form a stepped portion 68 between the low level surface 66 and the middle level surface 65. It is formed so as to protrude inward than position plane 65.

  Thus, one end of the oil hole 63 opens to the lower surface 66 in the vicinity of the portion where the two stepped portions 67 and 68 are bent and connected, and the oil scattered from the needle bearing 39 is stepped 67 and 68. And is easily guided to one end of the oil hole 63.

  Referring also to FIG. 5, the outer surface of the other crank web 16b facing the roller bearing 19 is provided with a recess 69 formed in an arc shape substantially corresponding to the roller bearing 19. The other end of the oil hole 63 is opened in the recess 69. Thus, the oil guided from the oil hole 63 is likely to be accumulated in the recess 69, and the oil can be supplied to the roller bearing 19 by scattering from the recess 69 to the roller bearing 19 side.

  In FIG. 2 again, the V-belt type automatic transmission M is provided in a transmission case 71 that covers a part of the engine body 11 from the side and is connected to the engine body 11 and extends to the left side of the rear wheel WR. The transmission case 71 is accommodated in the accommodation chamber 70. The transmission case 71 includes an inner case 72 integrally connected to the other case half 12b of the pair of case halves 12a and 12b constituting the crankcase 12, and the inner case. The outer case 73 is fastened to the inner case 72 so as to cover 72 from the outside, and the speed reducer case 74 is fastened to the rear portion of the inner case 72 in the outer case 73. A housing chamber 70 is formed between the inner case 72 and the outer case 73, and a gear chamber 75 is formed between the inner case 72 and the speed reducer case 74.

  The V-belt type automatic transmission M includes a drive pulley device 78 attached to the other end of the crankshaft 16 that enters the storage chamber 70 from the crankcase 12, and an inner case having an axis parallel to the crankshaft 16. 72 and a driven pulley device 79 mounted on an output shaft 81 rotatably supported by a reduction gear case 74, and an endless V-belt 80 that transmits power from the driving pulley device 78 to the driven pulley device 79. The

  The drive pulley device 78 includes a fixed pulley half 81 fixed to the crankshaft 16, a movable pulley half 82 that can approach and move away from the fixed pulley half 81, and an increase in the rotational speed of the crankshaft 16. The movable pulley half 82 has a stationary pulley half 81 as the centrifugal weight 83 moves radially outward as the number of rotations of the crankshaft 16 increases. It is urged in the direction approaching.

  In FIG. 6, the driven pulley device 79 includes an inner cylinder 87 that coaxially surrounds the output shaft 81 with a needle bearing 85 and a ball bearing 86 interposed between the output shaft 81 and relative rotation around the axis. An outer cylinder 88 in which the inner cylinder 87 is slidably fitted so as to be capable of relative movement in the axial direction, a fixed pulley half 89 fixed to the inner cylinder 87, and an outer cylinder facing the fixed pulley half 89 A movable pulley half 90 fixed to 88 and a component force in the axial direction is applied between both pulley halves 89 and 90 in accordance with a relative rotational phase difference between the movable pulley half 90 and the fixed pulley half 89. Thus, a torque cam mechanism 91 provided between the inner cylinder 87 and the outer cylinder 88, a spring receiving member 92 fixed to the inner cylinder 87 at a position sandwiching the movable pulley half 90 between the fixed pulley half 89, Enclose the outer cylinder 88 The coil spring 93 contracted between the movable pulley half 90 and the spring receiving member 92, and the inner cylinder 87 and the output shaft so as to be in a power transmission state as the engine speed exceeds the set speed. And a centrifugal clutch 94 provided between the two.

  And between the conical surfaces 81a and 82a of the fixed pulley half 81 and the movable pulley half 82 in the drive pulley device 78 and the cones of the fixed pulley half 89 and the movable pulley half 90 in the driven pulley device 79 opposite to each other. The V belt 80 is sandwiched between the surfaces 89a and 90a, and in the driving pulley device 78, the movable pulley half 82 approaches the fixed pulley half 81 as the crankshaft 16 rotates, thereby fixing the V belt 80. In addition, the winding radius of the movable pulley halves 81 and 82 is increased, and accordingly, in the driven pulley device 79, the V belt 80 is fixed and the wrapping radius of the movable pulley halves 89 and 90 is decreased.

  The fixed pulley half 89 is fixed to one end of the inner cylinder 87 by a plurality of rivets 95. The spring receiving member 92 is fixed to the other end of the inner cylinder 87. Thus, the spring receiving member 92 also constitutes a part of the centrifugal clutch 94, and the centrifugal clutch 94 includes a hook-shaped clutch outer 96 fixed to the other end of the output shaft 81, and the output shaft 81. The centrifugal weights 97 are pivotally supported at a plurality of locations of the spring receiving member 92 so as to be able to rotate around an axis parallel to the clutch receiving member 92, and the clutch weights 98 are provided between the centrifugal weights 97 and the spring receiving member 92. The centrifugal weights 97 are frictionally engaged with the clutch outer 96 when the centrifugal force acting on the centrifugal weights 97 in response to the rotation of the spring receiving member 92 exceeds the spring biasing force of the clutch springs 98. As a result, the inner cylinder 87, that is, the fixed pulley half body 89, and the clutch outer 96, that is, the output shaft 81 are coupled.

  The movable pulley half 90 is fixed to one end of the outer cylinder 88 by a plurality of rivets 102 so as to face the fixed pulley half 89. Further, the torque cam mechanism 91 includes cam holes 103 provided in a plurality of locations of the outer cylinder 88, cam pins 104 installed in the inner cylinder 87 so as to be inserted into the cam holes 103, and cam holes. 103... And a roller 105 that is pivotally supported by cam pins 104 so as to roll within the roller 103.

  Thus, the distance between the fixed pulley half 89 and the movable pulley half 90 in the driven pulley device 79 is determined by the axial force generated by the torque cam mechanism 91, the axial elastic force generated by the coil spring 93, and the fixed pulley. It is determined by the balance with the force from the V-belt 80 acting in the direction of separating the half body 89 and the movable pulley half body 90.

  The inner periphery of the coil spring 93 is guided by the guide member 106 on the movable pulley half 90 side, and a thrust bearing means 107 is interposed between the spring receiving member 92 and the coil spring 93.

  The guide member 106 has a flange portion 106 a that receives one end of the coil spring 93 on the movable pulley half 90 side, and is formed in a cylindrical shape with a self-lubricating resin. Is received by the flange 106 a of the guide member 106, and the inner periphery of the coil spring 93 on the movable pulley half 90 side is guided by the guide member 106. The guide member 106 is provided with a plurality of slits 108 extending from one end to the other end side and a plurality of slits 109 extending from the other end to the one end side.

  In addition, between the movable pulley half 90 and the outer cylinder 88 and the guide member 106 having the flange 106a, the flange 106a of the guide member 106 is received and one end of the coil spring 93 is inserted. A metal collar 110 formed in a cylindrical shape with a receiving portion 110 a formed in a substantially L-shaped longitudinal section at one end is interposed, and this collar 110 is provided on the outer cylinder 88. The outer cylinder 88 is coaxially surrounded so as to close the formed cam holes 103.

  By the way, each cam hole 103 and the annular chamber 111 formed between the output shaft 81 and the inner cylinder 87 between the needle bearing 85 and the ball bearing 86 are filled with grease. Are provided with communication holes 112 connecting between the annular chamber 111 and the respective cam holes 103. The annular seal member 113 elastically contacts the inner periphery of the collar 110 at the outer periphery of both axial ends of the outer cylinder 88. 113 are mounted on the inner periphery of both ends of the outer cylinder 88 in the axial direction, and annular seal members 114, 114 that are in sliding contact with the outer periphery of the inner cylinder 87 are mounted.

  The thrust bearing means 107 is made of a self-lubricating resin and a pair of bearing members 115 and 116 that are overlapped with each other, and are sandwiched between a coil spring 93 and a spring receiving member 92. A fitting cylindrical portion 115a fitted in a circular recess 117 provided in the spring receiving member 92 and a flat ring-shaped bearing portion 115b in contact with the closed end of the recess 117 are integrally provided, and the other bearing member 116 is provided. Is inserted into the inner periphery of the other end portion of the coil spring 93 so as to determine the relative position between the coil spring 93 and the flat plate ring-shaped bearing portion 116a sandwiched between the bearing portion 115b and the coil spring 93. And a positioning cylinder portion 116b integrally provided continuously on the inner periphery of the bearing portion 116a.

  Further, referring again to FIG. 2, the axle 118 of the rear wheel WR is rotatably supported by the speed reducer case 74 and the inner case 72, and the end of the axle 118 protruding from the transmission case 71 is attached to the engine body 11. It is rotatably supported by an arm 119 that is coupled and arranged on the right side of the rear wheel WR.

  A reduction gear train 120 provided between the output shaft 81 and the axle 118 is accommodated in the gear chamber 75. The reduction gear train 120 includes a first gear 121 provided on the output shaft 81, an output shaft 81, and A second gear 123 provided on the intermediate shaft 122 rotatably supported by the inner case 72 and the speed reducer case 74 in parallel with the axle 118 and meshed with the first gear 121, and a third gear provided on the intermediate shaft 122 124, and a fourth gear 125 that meshes with the third gear 124 and is provided on the axle 118.

  An outside air intake 126 for taking in cooling air into the accommodation chamber 70 is provided on a side wall of the outer case 73 facing the drive pulley device 78 in the transmission case 71, and the movable in the drive pulley device 78. A cooling fan 127 for dispersing cooling air taken from the outside air intake 126 into the housing chamber 70 is integrally provided on the outer periphery of the pulley half 90.

  Referring also to FIG. 7, the outer surface of the transmission case 71 is covered with a case cover 128 and a soundproof cover 129, and the case cover 128 includes a portion where the outside air intake 126 is disposed. The transmission case 71 is fastened to the outer case 73 of the transmission case 71 at a plurality of locations so as to cover the outer surface of the front half of the transmission case 71, and the soundproof cover 129 covers the rear side outer surface of the transmission case 71 on the side corresponding to the driven pulley device 79. It is fastened to the outer case 73 in the transmission case 71 at a plurality of locations so as to cover.

  In addition, the case cover 128 and the soundproof cover 129 are attached to the transmission case 71 so that the rear edge of the case cover 128 covers the front edge of the soundproof cover 129, and two of the two provided at the front of the soundproof cover 129 are provided. The boss portions 129a are sandwiched between the rear portion of the case cover 128 and the transmission case 71, and the rear portion of the case cover 128 and the front portion of the soundproof cover 129 are fastened to the transmission case 71 by the screw members 130.

  In addition, a suction port 131 opened rearward is formed between the rear edge portion of the case cover 128 and the front edge portion of the soundproof cover 129, and the suction port 131 is formed between the case cover 128 and the transmission case 71. An air introduction chamber 132 leading to is formed.

  A filter 133 is attached to the outer surface of the transmission case 71 so as to block the outside air intake 126 from the air introduction chamber 132 side, and the outside air introduced into the air introduction chamber 132 from the suction port 131 passes through the filter 133. By doing so, it is purified and sucked into the storage chamber 70.

  Referring also to FIG. 8, a space between the transmission case 71 and the soundproof cover 129 is defined as a plurality of spaces including at least one closed space, in this embodiment, three closed spaces. For example, four soundproof materials 137, 138, 139, and 140 are disposed so as to be partitioned into spaces 134, 135, and 136.

  Each of the soundproofing materials 137 to 140 is formed in a string shape by cutting and molding a urethane sheet, and one surface of the soundproofing materials 137 to 140 is either the transmission case 71 or the soundproofing cover 129 with an adhesive, In this embodiment, the soundproof cover 129 is adhered to the inner surface.

  Next, the operation of this embodiment will be described. In the driven pulley device 79 of the V-belt type automatic transmission M, at least the inner periphery of the coil spring 93 is guided by the guide member 106 on the movable pulley half 90 side, and the spring receiving member. Since the thrust bearing means 107 is interposed between the coil spring 93 and the coil spring 93, the coil spring 93 can be rotated together with the movable pulley half 90 so that relative rotation with the movable pulley half 90 does not occur. Further, it is possible to prevent the coil spring 93 from being twisted. In addition, since the inner periphery of the coil spring 93 is guided by the guide member 106 on the movable pulley half 90 side, the wavy phenomenon occurs in the coil spring 93 so that the inner periphery of the coil spring 93 is centered on the movable pulley half 90 side. It can be prevented from occurring.

  In particular, as the movable pulley half 90 moves in the axial direction, the amount of operation of the half of the coil spring 93 on the movable pulley half 90 side becomes relatively large. Since the inner periphery is guided by the guide member 106, it is possible to more effectively prevent the undulation phenomenon from occurring.

  Further, the thrust bearing means 107 is formed by sandwiching a pair of bearing members 115 and 116 that overlap each other between the coil spring 93 and the spring receiving member 92, and the thrust bearing means 107 can be configured with a very simple structure. In addition, since both the bearing members 115 and 116 are made of self-lubricating resin, even if the cooling air introduced into the storage chamber 70 contains dust, the wear resistance against dust can be improved. Can do.

  Further, the guide member 106 is also made of a self-lubricating resin, so that the inner periphery of the coil spring 93 and the sliding between the guide members 106 on the movable pulley half 90 side can be improved. As a result, the gap between the coil spring 93 and the guide member 106 can be set as small as possible, and it is possible to more effectively prevent the waviness phenomenon from occurring in the coil spring 93 and improve the operability.

  Further, since the metal collar 110 is interposed between the movable pulley half 90 and the outer cylinder 88 and the guide member 106 that receives the end face of the coil spring 93 on the movable pulley half 90 side, The thickness can be set thin, the gap between the guide spring 106 made of resin and the inner circumference of the coil spring 93 due to thermal expansion can be easily managed, and the difference in the coefficient of friction from the spring bearing member 92 side is maintained. Thus, relative rotation can be more reliably generated between the coil spring 93 and the spring receiving member 92.

  The space between the transmission case 71 and the soundproof cover 129 that covers the outer surface of the transmission case 71 and is attached to the transmission case 71 includes a plurality of spaces including at least one closed space by soundproofing materials 137 to 140, In the embodiment, since it is partitioned into three closed spaces 134 to 136, noise emitted from the transmission case 71 is absorbed by the soundproofing materials 137 to 140 disposed between the transmission case 71 and the soundproof cover 129. In addition to being suppressed, it is suppressed by preventing the sound resonance from occurring in the closed spaces 134 to 136 formed between the transmission case 71 and the soundproof cover 129, so that the space between the transmission case 71 and the soundproof cover 129 is reduced. Noise is sufficient with a simple structure in which soundproofing materials 137 to 140 are partitioned into a plurality of closed spaces 134 to 136. It is possible to obtain the stop effect.

  Here, A is a state where there is no sound absorbing material between the soundproof cover 129 and the transmission case 71, B is a state where there is a sound absorbing material over the front surface between the soundproof cover 129 and the transmission case 71, and between the soundproof cover 129 and the transmission case 71 according to the present invention. 9 is a state in which the sound-insulating materials 137 to 140 are partitioned into a plurality of closed spaces 134 to 136, and the noise generation state at the time of acceleration of the motorcycle in each of the states A to C is tested. The results shown in FIG. It can be seen that an excellent noise prevention effect can be obtained in the state C according to the present invention.

  The soundproofing materials 137 to 140 are formed in a string shape by cutting and molding a urethane sheet, and one surface of the soundproofing materials 137 to 140 is either the transmission case 71 or the soundproofing cover 129 by an adhesive. In the embodiment, since it is attached to the soundproof cover 129, the yield when forming the soundproof materials 137 to 140 is increased as compared with the conventional one using a sheet-like soundproof material having a shape corresponding to the shape of the soundproof cover 129. In addition, since the soundproof cover 129 can be attached to the transmission case 71 in a state where the soundproofing materials 137 to 140 are bonded to either the transmission case 71 or the soundproof cover 129, the productivity when the power unit P is assembled is improved. To do.

  Further, an outside air intake 126 for taking in cooling air into the accommodation chamber 70 is formed on the side wall of the transmission case 71 at a portion facing the drive pulley device 78 of the V-belt type automatic transmission M accommodated in the accommodation chamber 70. Although provided, the soundproof cover 129 is formed in a shape covering substantially half of the outer surface of the transmission case 71 on the side corresponding to the driven pulley device 79 in the V-belt type automatic transmission M. The productivity can be improved by arranging the soundproofing materials 137 to 140 between the transmission case 71 and the soundproofing cover 129 without considering the outside air intake 126 provided in the case 71.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

It is a side view of a power unit and a rear wheel. FIG. 2 is a sectional view taken along line 2-2 of FIG. FIG. 3 is an enlarged view of a main part of FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. It is an expansion cross-sectional view of a driven pulley apparatus. It is the figure which looked at the case cover and the soundproof cover from the 7-7 line arrow direction of FIG. It is the figure which looked at the case cover and the soundproof cover from the 8-8 line arrow direction of FIG. It is a figure which shows the test result of a noise generation condition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Engine main body 70 ... Accommodating chamber 71 ... Transmission case 78 ... Drive pulley device 79 ... Driven pulley device 126 ... Outside air intake port 129 ... Soundproof cover 134-136 ... -Closed space 137-140 ... Soundproof material M ... Transmission P ... Power unit WR ... Rear wheel as drive wheel

Claims (3)

  A transmission case (71) forming a storage chamber (70) for storing the transmission (M) is covered on the engine main body (11) from the side and a drive wheel (WR) side. In the power unit in which the soundproof cover (129) is attached to the transmission case (71) so as to cover the outer surface of the transmission case (71), the transmission case (71) and the soundproof cover (129) ) Are provided between the transmission case (71) and the soundproof cover (129). The soundproof material (137-140) partitions the space between the transmission case (71) and the soundproof cover (129). A soundproof structure for a power unit.   One surface of the soundproof material (137 to 140) formed in a string shape by cutting and molding a urethane sheet is bonded to either the transmission case (71) or the soundproof cover (129) with an adhesive. The soundproof structure in the power unit according to claim 1.   The transmission (M) is a V-belt type automatic transmission including a driving pulley device (78) and a driven pulley device (79), and an outside air intake (126) for taking cooling air into the accommodation chamber (70). ) Is provided on the side wall of the transmission case (71) at a portion facing the drive pulley device (78), and the soundproof cover (129) is disposed on the side corresponding to the driven pulley device (79). 71) The soundproofing structure in the power unit according to claim 1 or 2, wherein the soundproofing structure is formed so as to cover a substantially half portion of the outer surface of 71).

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